The present invention relates to a base station (BS) and a mobile station (MS) which perform information distribution in a mobile radio communication system structured by a BS and plural MSs.
In a mobile radio communication system, a reception channel is generally provided for paging a MS (incoming call).
Personal Handy phone System (PHS) is a mobile radio communications system using TDMA/TDD technology. In a PHS, one frame of 5 ms is divided into each four time slots of uplink and downlink communications. Of each four time slots of uplink and downlink communications, time slots used for transmission/reception of a control signal are one time slot of uplink and downlink communications, respectively. A time slot for transmission of control information structures a super frame of which cycle is 1.2 seconds. A super frame refers to the minimum cycle of a downlink Logical Control Channel (LCCH) which designates slot positions of all LCCH elements.
The downlink LCCH elements refer to a Broadcasting Control Channel (BCCH: information channel) used in the system, a Paging Channel (PCH: simultaneous paging channel) corresponding to all incoming calls, a Signaling Control Channel (SCCH: channel for individual cells) inserted in a fixed manner, and a User Specific Control Channel (USCCH). The BCCH (A) is necessarily transmitted at the front slot of the LCCH super frame. However, any one of other LCCH elements may be stolen temporarily so that other LCCH elements are transmitted, as needed. The LCCH is stored in the downlink control time slot at a cycle of 5×n (ms) (wherein n is an interval value of the LCHH). For example, the LCCH interval value (n) in a PHS is 20, which is determined by the standard for public, therefore a BS transmits various control information at an interval of 100 ms. Paging information is transmitted to each incoming call at an interval of one super flame (1.2 seconds).
Even when there is no paging information, a BS transmits an idol PCH. A paging message sores information with 62-bit structure, such as an identification number of a receiving MS.
A USCCH is a User Packet Channel (UPCH) capable of being defined on a control physical slot. Herein, the UPCH is a bidirectional channel between a point and multiple points, which performs transmission of the user packet data. The USCCH is a voluntary option in a PHS as long as the USCCH satisfies the specified items. In addition, the USCCH includes USCCH (1) and USCCH (2), wherein the USCCH (1) includes an arrival identification code and arrives at a certain terminal while the USCCH (2) does not include an arrival identification code.
A BS and a MS are not dependent on a system in this specification. A BS and a MS in a PHS are referred to as a Cell Station and a Personal Station, respectively, which are hereinafter described as “CS” and “PS”. On the other hand, a BS and a MS in a Ultra Mobile Broadband (UMB) are referred to as an Access Point and an Access Terminal, respectively, which are hereinafter described as “AP” and “AT”.
A system in which information is distributed from a distribution center to a PS in PHS will be described with reference to FIG. 1. Herein, FIG. 1 is a block diagram illustrating the information distribution in a PHS. In FIG. 1, an information distribution system 100 in PHS is structured by a distribution center 10, an exchange device 20 (hereinafter, referred to as “EX”), a CS (Cell Station) 30, and PSs (Personal Stations) 70. In a conventional distribution method, a distribution center determines a simultaneous paging area where information is to be delivered and transmits the information to each PHS of which a location is registered in the simultaneous paging area. With reference to FIG. 1, it is assumed that there are four CSs of CS 30-1, CS 30-2, CS 30-3, and CS 30-4, in a certain simultaneous paging area 80. Eight PSs 70 are registered in the simultaneous paging area 80. When the distribution center 10 designates information distribution to the simultaneous paging area 80, each PS 70 of which a location is registered in the simultaneous paging area 80 is alerted. Therefore, the distribution center 10 transmits information to EX 20 in the simultaneous paging area 80, then EX 20 transmits a set up message incorporating the distribution information to all CSs in the area: CS 30-1, CS 30-2, CS 30-3, and CS 30-4. When receiving the set up message from the EX 20, each CS transmits a PCH to the PS 70 which is in a waiting state thereof.
As described above, a conventional distribution system is distribution in a unit of a simultaneous paging area unit. Accordingly, information distribution cannot be performed to a more limited area than a department store or the like. Furthermore, since the CS transmits the PCHs to as many as the number of PSs, the limited PCH resources are sometimes lacking, thereby resulting in a failure of arrival of a usual incoming call.
In a conventional distribution system, an information distribution sequence in which information is distributed from a distribution center to a PS will be described with reference to FIG. 2. Herein, FIG. 2 is a sequence diagram illustrating information distribution among a distribution center, an EX, CSs, and PSs.
In FIG. 2, the distribution center 10 transmits information to the EX 20 in a simultaneous paging area designated as a distribution destination (T201). When receiving the information, the EX 20 transmits a setup message incorporating the distribution information to CSs 30 (note that only the CS 30-1 and the CS 30-2 are illustrated for simplification of the drawing) arranged in the simultaneous paging area (T202, T204). When receiving the set up message from the EX 20, the CS 30-1 and the CS 30-2 transmit the PCH to PSs (note that only PS 70-1 and PS 70-3 are illustrated) which is in a waiting state thereof (T203, T206). When confirming that an incoming call number of the received PCH is identical with its own number, the PS 70-3 transmits an LCH establishment request to the CS 30-2 (T207), and transmits/receives a message for connecting a Traffic Channel (TCH). The CS 30-2 transmits a set up message (LCH Assignment) incorporating distribution information to the PS 70-3 (T208).
When the PS 70-3 fails to receive the information because of any cause occurring between the CS 30-2 and the PS 70-3, the CS 30-2 sometimes attempts to transmit the information again; however, in the case of a further failure, the PS 70-3 cannot take this distribution information. In addition, since a TCH is used for distributing information, the PS 70-3 sometimes cannot perform a usual transmission because of lack of TCH. Furthermore, the battery of the PS 70-3 is exhausted by transmitting/receiving a message for performing TCH connection between the PS 70-3 and the CS 30-2. T209 to T224 are usual procedures, such as paging response, authentication, call connection, and call disconnection, thus explanation regarding these procedures will be omitted.
The case of PHS has been described above; however, this description can be adopted in other mobile radio systems, even in a system with a reception function. A UMB is a mobile radio communication system using Orthogonal Frequency Division Multiplexing Access/Frequency Division Duplex (OFDMA/FDD) technology. There is a message for paging an incoming call even in the UMB and when there is no incoming call, an idle message for incoming call is transmitted. In the UMB, what is called the PCH in PHS is referred to as a Quick Page Channel (QPCH), and what is called the TCH is referred to as a Data Channel (DCH).
“The second generation cordless telephones system, ARIB RCR STD-28 4.0 edition, pages: 66, 71 and 86, March, 2002, Research & Development Center for Radio System” describes the definition of the USCCH, a super frame structure of the downlink LCCH, and a structure of the USCCH (2) which is a physical expansion slot.
“3GPP2 C. S0084-002-0 version 2.0, 3-5 pages, July, 2007, 3RD GENERATION PARTNERSHIP PEOGECT 2” describes how to use a reception channel in a UMB system.
In the above information distribution method, a short message is transmitted to each PS to be targeted in the area. To transmit a short message to a PS, all CSs belonging to a simultaneous area transmit PCHs. In the case where there are many PSs to be targeted, the number of transmissions of PCHs increases in accordance therewith, thus the limited PCH resources may be insufficient. In the case, a usual incoming call sometimes fails to arrive because of lack of PCH resources. When the first message failed to be received, the message can be transmitted again; however, the retransmission thereof may fail again because of an adverse influence by a radio wave environment, resulting in a failure that the PS does not take the distribution information.
Each CS and each PS connect TCHs thereof together and perform a short message distribution on the TCH. Therefore, when distributing information, the number of the TCH traffics increases, resulting in that a usual transmission sometimes cannot be performed because of lack the TCH resources or the like. In addition, it is counted as one usual incoming call because the information distribution is performed on the TCH. As a result, the battery is more exhausted than that in a usual waiting state.
The distribution center designates a simultaneous paging area where the information is to be distributed and distributes the information to each PS of which a location is registered in the area. Therefore, the information distribution is performed in a wider unit of so-called a simultaneous paging area, resulting in failure of distribution to a more limited area than a department store or a store or the like.
In the above information distribution method, each CS and each PS connect their TCHs together and perform information distribution on the TCH. Accordingly, it is counted as one usual incoming call; thereby the battery is more exhausted than that in a waiting state. When there is a lot of distribution information, much of the battery is exhausted.
The above problems are the same as UMB.